Edge roll control for wheel rolling mills



March 9, 1965 E. H. KENDALL 3,172,311

EDGE ROLL common FOR WHEEL ROLLING MILLS Filed Oct. 3, 1961 2 Sheets-Sheet 1 E. H. KENDALL EDGE ROLL CONTROL FOR WHEEL ROLLING MILLS March 9, 1965 2 Sheets-Sheet 2 Filed Oct. 5, 1961 United States Patent 3,172,311 EBGE ROLL CUNTROL F613 WHEEL RQLLIN lvilLLS Edgar Homer Kendall, deceased, by First National Qrty Bank of Alliance, executor, Alliance, Ohio Filed Get, 3, 1% Ser. No, 142,737 4 Qiaims. (til. 72-3) The present invention relates to the art of rolling metal discs or wheels, such as railway car wheels, for example, and more particularly to an improved and simplified system for controlling the manipulation of the pair of opposing work rolls which are commonly employed in wheel rolling mills to engage and form the webs and rims of such products. The invention is particularly applicable to wheel rolling mills of the general kind disclosed in detail in US. Patent Nos. 2,763,168 and 2,993,393 issued to the inventor of the present disclosur In wheel rol ing mills of the kind above mentioned, the preformed (forgedlblanks are loaded horizontally into a rolling station wherein the blanks are adapted to be retained and worked by two clusters of diametrically opposed rolls, one of which clusters comprises a main or anvil roll accompanied on either side by a guide roll, and this first cluster moves radially outwardly of the center of the blank under a controlled back pressure as the blanks expands in diameter. The main or anvil roll is driven and assists in forming the outer periphery of the rim ofthe wheel. The rolls of the second cluster include a pair of driven edge rolls which engage the top and bottom surfaces of the horizontally disposed workpiece to form the web thereof. These rolls operate in a generally fixed vertical plane normal to the common axis of the two clusters but they are mounted for movement toward and away from each other so that the thickness and shape of the web can be controlled during the rolling operation. In nesting relation with these edge rolls and on either side thereof are a pair of pressure rolls which are coupled by a crosshead and arranged to move, under force, toward and away from the first mentioned roll cluster. At the start of a rolling cycle the workpiece is so positioned that as the edge rolls close onto it they engage the same in the center portion or hub thereof. As the rolling proceeds, the crosshead carrying the pressure rolls is controllably advanced under power so that the workpiece is shifted normal to its rotational axis, i.e., horizontally between the edge rolls, and the .gap or spacing between the edge rolls is controllably varied synchronously with such movement to effect the proper tapered rolling of the web of'the wheel. When the rim structure of the wheel blank reaches the edge rolls the latter cooperate with the adjacent pressure rolls to give the final desired cross sectional shape and outer diameter to the rim section of the wheel, which shaping is also, of course, aided by the action of the main or anvil roll of the first mentioned (retracting) cluster of rolls.

In view of all of the above and of other factors including variations in temperature and in the quality of forging of the workpieces, it should be obvious that the controlling of the wheel mill during a rolling operation is a complex operation which can be controlled only by one thoroughly experienced in the art. First, if the mill is to have a high rate of production and if the wheels are to be rolled at an optimum temperature it is necessary to provide means to rapidly but controllably open and close the roll passes between the working rolls, particularly the edge rolls, for the rapid loading and unloading of the mill and, secondly, means must be provided to limit the initial closing of the edge rolls to more or less automatically control the initial thickness of the Web. This is very important in order that as the wheel is worked outwardly toward the rim adequate metal is available to achieve the proper diameter of the wheel and the rigidly prescribed minimum thickness of the web. Also, the web must be formed with a predetermined taper, and the combined requirements of an accurate inner or initial web thickness and a predetermined taper has heretofore posed considerable diificulty resulting in a lower rate of production and a substantial number of rejects for substandard rolling. While it is relatively easy to measure and/ or observe the growth and dimension of the outer diameter of the wheel, it is dimcult to measure and/or observe the formed thickness and taper of the web, and although instruments have been proposed for the latter purpose the same are not entirely satisfactory as regards dependability and useful life.

It is accordingly the primary object of the invention to provide a simplified and improved system for controlling the most critical phase of the operation of a wheel rolling mill which is the continuing control of the gap or spacing between the two edge r'olls during a rolling operation. This general improvement is accomplished, in accordance with the present invention by providing a simple and fastacting control for rapidly opening and closing the edge rolls in loading and unloading and for rapidly bringing the edge rolls into proper spaced relation for initiating the rolling of the tapered web. While normally this aspect of the control may be manual, in some highly repetitive operations it may be desirable to integrate the same into an automatic sequence control. However this primary control aspect is handled, it is a salient feature of this invention that immediately upon said edge rolls reaching the required degree of closing onto the workpiece to effect the initial or root thickness of the web, an automatic proportioning control takes over which so brings the edging rolls closer together in relation to the translational movement of the workpiece that the proper prescribed taper is automatically imparted to the web. This relieves the operator of much personal attention, and results in a higher rate of production of acceptable products from the mill.

The above and other objects and advantages of the invention will become apparent upon consideration of the following specification and the accompanying drawing wherein there is disclosed a preferred embodiment of the invention.

The sole figure of the drawing, on two sheets, is a schematic showing of certain of the essential elements of the wheel rolling mill to which the present invention is applicable and of the hydraulic and electrical circuit used to control the edge rolls of the mill in accordance with the teaching of this invention. For a more complete showing of the rolling mill, proper reference should be had to the aforementioned U.S. Patent No. 2,763,168.

In the present drawing, reference numerals 10 and 1-1 designate the upper and lower edge rolls, respectively, of the wheel rolling mill, and in accordance with known practice these rolls are carried and driven by spindles, not shown, journaled within the elongated housings 12 and 13. These housings are pivotally mounted, as at 14, in a heavy frame, not shown, of the mill whereby the rolls 1% and 11 may be moved toward or away from each other, if desired. It will be understood that the axes of the rolls 10 and .1-1 lie in the common vertical plane so that the work-engaging portions of the rolls are always substantially directly opposite each other when engaging the workpiece, which workpiece is herein shown as a formed railway car wheel 15. As explained above, the workpiece 15 is loaded in the mill in a horizontal position and in addition to being clamped by the edge rolls 10 and 11 is engaged diametrically by an anvil roll 16 and a pair of pressure rolls 1? which latter are received, in nesting relation, on either side of the edge rolls 1t) and ii. The guide rolls normally associated with the anvil roll 16 are not shown herein, nor is the crosshead support for the pressure rolls 17, nor the power means for advancing this crosshead and consequently the pressure rolls 17 to the left as the anvil roll 16 is controllably retracted to the left during a rolling operation.

Since it is common practice in the manufacture of wrought steel railway wheels to cone the wheel in a press after rolling whereby the hub is displaced axially with respect to the rim it is only necessary to manipulate one of the edge rolls during the rolling cycle. Thus, the vertical position of the lower edge roll 11 may remain fixed during a rolling cycle, and accordingly the control system of the present invention is applied only to the upper edge roll 10. The roll-end portion of the housing 12 is pivotally connected at 18 to a crosshead 19 which mounts a ram 20 received in the large cylinder 21. Member 21 is pivotally mounted by suitable pintles, not shown, on the axis 22 to the frame of the mill which carries the pivot point 14. Cylinder 21 has outrigger extensions 23 on each of which is supported a double-acting pull-back cylinder 24 having a piston therein which is connected through a rod 25, crosshead 26, and rods 27 to the crosshead 19.

For supplying hydraulic fluid pressure to the cylinders 21 and 24 there is provided a pump 28 which normally is continuously driven by a motor, not shown, and which is of the variable delivery type under the control of an hydraulic actuator shown schematically at 29. Fluid from a suitable pressure source, not shown, is metered into opposite ports of the control 29 by an electro-hydraulic servomechanism 30 which operates in response to the strength of signals impressed by an input circuit 31 to control the output of the pump 28 from Zero to maximum volume.

The output of pump 28 is conducted through conduits 33, 34 and 35 to the rod ends of cylinders 24 so that at the start of a cycle of operation when the edge roll is fully retracted (raised) unit 30 may be manually controlled as hereinafter to be explained to result in the delivery of hydraulic fluid at a maximum rate and consequently in the rapid downward movement of the edge roll 10. Branching off from the conduit 33 is a conduit leading into the cylinder 21 in which is interposed a spring-loaded valve 36 which operates to withhold the fluid from the cylinder 21 during such initial downward movement of the upper edge roll.

Mounted directly on the top of the cylinder 21 and communicating therewith is a large pre-fill valve shown schematically at 37 which is connected with a fluid reservoir 38 and which is operative when opened to allow large volumes of fluid to be moved from the reservoir 38 into the cylinder 21 and vice versa. Pre-fill valve 37 has a valve plunger 39 which. when moved to the left (as viewed in the drawing) under action of a biasing spring 40 establishes communication between the reservoir 38 and the cylinder 21. For moving the valve plunger 39 in a closing direction against the spring 40, there is provided a cylinder and piston 41 which receives fluid under pressure directly from the conduit 33 through a conduit 42. The force of the spring 40 in relation to the cross sectional area of the cylinder 41 is such that the plunger valve 39 will not begin to move in the closing direction until a pressure has been developed in conduits 33 and 42 which is approximately the releasing pressure of the valve 36. Interconnecting the bottom ends of the cylinders 24 with the inlet port of the pump 28 is a conduit 43 in which is interposed a solenoid actuated two way valve 44 having an operating coil 44C. As will appear hereinafter, when the control system is actuated to initiate the descent of the edge roll 10 from its upper retracted position, the solenoid of valve 44 remains de-energized to hold the valve open and thus permit a maximum rate of return flow from the bottom ends of the cylinders 24 and thus effect maximum downward rate of movement of the upper edge roll. In parallel with the valve 44 is a spring-loaded relief valve 45 which operates upon closure of valve 44 to rather abruptly inten'upt the downward movement of the upper edge roll 10 while yet permitting continued downward movement thereof under a substantial back pressure. This back pressure is suflicient to allow a build-up of pressure in conduit 33 to open valve 36 and shift the plunger of the pre-fill valve 37 to closed position. The control mechanism by which this transition is made and through which the above described taper control is eifected will now be described.

Since the downward pressure exerted by cylinders 24 is insuflicient to eifect any rolling action, the large ram cylinder 21 must be energized at the start of actual rolling. This is accomplished by the limit switch 67 which energizes solenoid 440 from a suitable current source 678 through circuit 67C. Limit switch 67 is arranged to be closed by an actuator 67A shown as being carried by one of the tie rods which interconnect the piston rod of one of the cylinders 24 with the crosshead or platen 19. The location of actuator 67A is so adjusted that switch 67 is closed when the upper work roll 10 closely approaches the workpiece during lowering movement of this roll. Further, the actuator is so constructed that it holds switch 67 closed during the whole of the rolling cycle.

Arranged to be operated by the further downward movement of the platen 19 is a second adjustable limit switch 46 which is normally open and which is so adjustably mounted that it closes precisely when the top edge roll 1% has descended to a vertical position coincident with the proper initial web thickness of the wheel to be rolled. The position of the switch 46 is periodically checked in relation to the wear of the edge rolls and to the precision of the finished product so that the switch is closed when the upper edge roll 19 reaches the vertical position necessary to give the precise initial or root thickness to the tapered web to be rolled. Up to this point, in the cycle of operation, the downward movement of the upper edge roll 10 is under manual control, as will hereinafter appear, to allow the operator to rapidly close the work rolls onto the workpiece, to accurately oifset the center axis of the wheel in relation to the start of the web rolling, and to allow him to apprise the temperature and stiffness of the workpiece. Thereafter the rolling of the web proceeds semi-automatically by reason of the followmg.

In accordance with the principles of this invention there are provided three transformers having movable armatures which as is well known in the positional control art, are operative to determine the extent of linear displacement of the armatures with great precision, the output or reading of these instruments being in the form of voltages which are commonly fed to amplifiers and to comparators or other similar control instrumentalities. In the present invention one of these linear voltage detecting transformers designated by reference numeral 47 is arranged to have its armature carried by the crosshead 19 so that a voltage will be generated in its output circuit 48 which is precisely proportional to the vertical position of the crosshead 19 and consequently of the upper edge roll 10. Of course, the windings of the transformer 47 or its armature are, in practice, vertically adjustable for zeroing-in purposes. A similar position-responsive voltage generator 49 having an output circuit 50 is arranged to have its armature actuated by a cam 51 rigidly carried by the slideable bearing housing 52 of the anvil roll 16. In practice, the cam 51 is properly dimensioned and contoured to reproduce the taper which it is desired to roll on the web of the workpiece and therefore the generator 49 may be considered as the command generator while the generator 47 may be considered as the feedback or error generator. The outputs of these generators are fed through their output circuits 48 and 50 to an electronic combined amplifier and comparator shown schematically at 53. The net result of the com- .parison of the instantaneous voltages appearing in .cir-

cuits 48 and St? is expressed in a voltage or signal applied to the output circuit 54 of the network 53 and, as shown, this latter voltage or signal is impressed on the control or input circuit for the electrohydraulic servomechanism 36 through a contactor 55 of a relay 56 having an operating coil 57.

The above various electrical components are so calibrated and/ or adjusted that when the armature of generator 4? is at the starting point of the cam 51 and the limit switch 46 has just closed the signals in circuits 43 and 51} will be balanced and there will be no output in circuit 54- to energize the electro-hydraulic servomechanism 30. Consequently, the downward movement of edge roll will be stopped and will not be resumed until a lower portion of the cam 51 acts on the armature of the generator 49. Prior to the closing of switch 46 at the start of a taper-rolling cycle the contactor 55 of relay 56 is operative to connect the third or manual signal voltage generator 58 to the input circuit 31 of the electro-hydraulic servo unit 30. Upon initial energization of relay 55 its operating coil 57 is locked in across the electrical energizing source 575 by a contactor 59 on the relay and the normally closed limit switch 66. This latter limit switch 60 is adjustably mounted below the limit switch 46 to open exactly when the specified minimum thickness is obtained in the web being rolled on the wheel.

In operation of the wheel rolling mill and the control apparatus thus far described, all functions are under the manual control of the operator until the edge rolls are squeezed down onto the work to give the maximum or root thickness of the tapered web to be rolled in the workpiece. Thereafter, as the wheel expands or grows in diameter as a result of the rolling action and the anvil roll 16 moves to the left, as viewed in the drawing, the edge rolls will automatically come closer together to effect the prescribed degree of taper in the web of the wheel. it should also be obvious, and contributing very substantially to the utility of this invention, is the fact that the operator may, if he finds the same necessary or desirable, reroll inner portions of the web without losing his slope or taper in the web. In actual practice this back-andiorth rolling is accomplished by manipulating the relative forces applied to the anvil roll 16 and the pressure roll 17. Not only does this additional rolling increase the strength of the wheel but it is necessary in some instances to produce an acceptable product when the workpiece is cool or exceedin ly stiff, for example. tage of the invention is that once the preset root thickness is achieved in the web on the proper diameter of the wheel it is most unlikely that the minimum prescribed root thickness will be achieved until the wheel has grown to its proper size. This greatly facilitates the work of the roller or operator and results in fewer production rejects.

To return the upper edge roll to its initial retracted position at the end of a rolling cycle and thereby permit the rapid unloading and reloading of the mill, there are provided additional solenoid-operated valves 61 and 62, the first of which when energized is operative to block the supply of fluid pressure from pump 28 to the rod ends of cylinders 24 and to connect this fluid pressure to the bottom ends of these cylinders. Valve 62 is normally closed and when energized opens to connect the rod ends of the cylinders 24 to the inlet port of the pump 28. As shown, the solenoids 51C and 62C for the valves 61 and 62, respectively, are arranged to be energized through normally open contactors of a relay 63 having an operating coil 64. Operating coil 64 is energized -from a suitable source through a normally closed contactor 65 on relay 56 and a series connected manual normally-closed push button 66. It will thus be seen that immediately upon minimum thickness being obtained in the web of the wheel being rolled the hydraulic circuits will be conditioned to raise the upper edge roll 16 under the manual Another advancontrol 58 since opening of the limit switch 60 de-energized relay 56 to restore such manual control and to energize relay 64. Of course, the operator can readily control the rate of upward movement of the upper edge roll and he can also readily stop the same in any vertical position he deshres. However, he cannot condition the system for closing movement of the edge rolls without first depressing the push button 66 to de-energize the operation coil as of the relay 63. A suitable interlock, not shown, may be provided to hold the switch 66 open and the relay 63 thus de-energized until closure of switch 46 energizes relay 56 to open contactor 65. Alternatively, the switch 56 may be combined with a manual control for signal generator 58 so that it may be manually held off until the relay 56 is energized.

It should now be apparent that the invention accomplishes the objects initially set out, particularly as regards the improved and simplified arrangement for integrating the taper control into the general control system for the mill. inany position of the upper edge roll it above an actual rolling position the opening'and closing of the edge rolls is automatically under manual control with the hydraulic system conditioned for rapid traverse which, of course, enables the mill operator to proceed with loading and unloading in a minimum period of time and with minimum manipulation or movement of the upper roll housing 12. The flexibility afforded by the manual control of the initial rolling penetration of the roll 19 is highly advantageous for reasons pointed out above and, of course, the sequential automatic taper control is of prime benefit in rapidly producing accurately formed wheels.

It should be understood that the above specifically described and illustrated embodiment of the invention is only for the purpose of best explaining the principles of the invention and that many changes may be made therein without departing from such principles. Reference should therefore be had to the appended claims in determining the scope of the invention.

What is claimed is:

1. In a wheel rolling mill of the kind having a pair of edge rolls for engaging the opposite sides of a wheel blank to roll a tapered web therein and means to shift the wheel blank normal to its rotational axis and with respect to the pass between said edge rolls as well as a double-acting fluid motor to move one of said edge rolls toward and away from the other of said edge rolls; the improvement comprising the combination of a variable delivery pump for supplying hydraulic fluid under pressure to said motor, an electro-hydraulic servomechanism for controlling the output of said pump, means to generate an electrical signal proportionate to the gap dimension between said rolls, means to generate a second electrical signal proportionate to the shifted position of said wheel blank relative to said rolls, a third manually controlled signal generator having circuit means normally connecting the output thereof with said servomechanism, means to compare the output of said first and second mentioned signal generators and to impress the result thereof onto a control circuit, a second control circuit operative when activated to disconnect said servomechanism from said manually controlled signal generator and to connect the same to the first mentioned control circuit, a first limit switch adapted to be actuated upon said one of said edge rolls reaching a predetermined position when moving inwardly toward the other of said edge rolls to activate said second control circuit, and a second limit switch adapted to be actuated upon the said one of said edge rolls reaching a predetermined further inward position with respect to the other of said rolls to de-activate the said second control circuit thereby restoring said pump to manual control.

2. A control system according to claim 1 further including means automatically actuated upon actuation of said second limit switch to reverse the direction of flow of hydraulic fiuid from said pump to said motor Whereby the said one of said edge rolls may be retracted at a speed determined by the setting of said manual controlled signal generator.

3. A control system according to claim 2 further characterized in that said second control circuit comprises a relay having an operating coil adapted to be energized by the closing of said first limit switch, said relay having a holding circuit adapted to be opened by the actuation of said second limit switch, said relay having a normallyclosed contact operative to actuate said means to reverse the direction of flow of hydraulic fluid from said pump to said motor, and a normally-closed switch in series with said normally-closed contactor.

4. In a Wheel rolling mill of the kind having a pair of edge rolls for engaging the opposite sides of a wheel blank to roll a tapered web therein and means to shift the wheel blank normal to its rotational axis and with respect to the pass between said edge rolls, a double-acting fluid motor to move one of said edge rolls toward and away from the other, a hydraulic ram for moving the said one of said edge rolls toward the other, and a normally-open fiuid-pressure-operated pre-fill valve interconnecting said ram with a reservoir; the improvement comprising the combination of a variable delivery pump for supplying hydraulic fluid under pressure to said 1110- tor and ram, means to manually control the output of said pump, means to automatically control the output of said pump in accordance with the instantaneous spacing of said rolls in relation to the diametric position of said wheel blank between said rolls, conduit and valve means to initially supply the manually controlled output of said pump to one end of said motor to effect a quick-closing movement of said rolls, and means automatically responsive to said rolls reaching a predetermined closed position to direct the output of said pump to both said ram and to the said one end of said motor, and means responsive to a predetermined further closing of said rolls to shift the control of said pump from said manual means to said automatic means.

References Cited by the Examiner UNITED STATES PATENTS 2,091,578 8/37 Batie 8016 2,406,219 8/46 Hight et a1. 8016 2,993,393 7/61 Kendall 80-46 WILLIAM J. STEPHENSON, Primary Examiner.

LEON PEAR, Examiner. 

4. IN A WHEEL ROLLING MILL OF THE KIND HAVING A PAIR OF EDGE ROLLS FOR ENGAGING THE OPPOSITE SIDES OF A WHEEL BLANK TO ROLL A TAPERED WEB THEREIN AND MEANS TO SHIFT THE WHEEL BLANK NORMAL TO ITS ROTATIONAL AXIS AND WITH RESPECT TO THE PASS BETWEEN SAID EDGE ROLLS, A DOUBLE-ACTING FLUID MOTOR TO MOVE ONE OF SAID EDGE ROLLS TOWARD AND AWAY FROM THE OTHER, A HYDRAULIC RAM FOR MOVING THE SAID ONE OF SAID EDGE ROLLS TOWARD THE OTHER, AND A NORMALLY-OPEN FLUID-PRESSURE-OPERATED PRE-FILL VALVE INTERCONNECTING SAID RAM WITH A RESERVOIR; THE IMPROVEMENT COMPRISING THE COMBINATION OF A VARIABLE DELIVERY PUMP FOR SUPPLYING HYDRAULIC FLUID UNDER PRESSURE TO SAID MOTOR AND RAM, MEANS TO MANUALLY CONTROL THE OUTPUT OF SAID PUMP, MEANS TO AUTOMATICALLY CONTROL THE OUTPUT OF SAID PUMP IN ACCORDANCE WITH THE INSTANTANEOUS SPACING OF SAID ROLLS IN RELATION TO THE DIAMETRIC POSITION OF SAID WHEEL BLANK BETWEEN SAID ROLLS, CONDUIT AND VALVE MEANS TO INITIALLY SUPPLY THE MANUALLY CONTROLLED OUTPUT OF SAID PUMP TO ONE END OF SAID MOTOR TO EFFECT A QUICK-CLOSING MOVEMENT OF SAID ROLLS, AND MEANS AUTOMATICALLY RESPONSIVE TO SAID ROLLS REACHING A PREDETERMINED CLOSED POSITION TO DIRECT THE OUTPUT OF SAID PUMP TO BOTH SAID RAM AND TO THE SAID ONE END OF SAID MOTOR, AND MEANS RESPONSIVE TO A PREDETERMINED FURTHER CLOSING OF SAID ROLLS TO SHIFT THE CONTROL OF SAID PUMP FROM SAID MANUAL MEANS TO SAID AUTOMATIC MEANS. 